Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60G—VEHICLE SUSPENSION ARRANGEMENTS
  • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
  • B60G17/02—Spring characteristics, e.g. mechanical springs and mechanical adjusting means
  • B60G17/04—Spring characteristics, e.g. mechanical springs and mechanical adjusting means fluid spring characteristics
  • B60G17/056—Regulating distributors or valves for hydropneumatic systems
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/20—Control of fluid pressure characterised by the use of electric means
  • G05D16/2093—Control of fluid pressure characterised by the use of electric means with combination of electric and non-electric auxiliary power
  • G05D16/2097—Control of fluid pressure characterised by the use of electric means with combination of electric and non-electric auxiliary power using pistons within the main valve
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/7504—Removable valve head and seat unit
  • Y10T137/7613—Threaded into valve casing

Definitions

• This invention relates to two stage pressure control valves, and in particular to such a valve specially adapted to control fluid flow in a vehicle suspension damper.
• U.S. Patent Number 5,069,420 discloses a predecessor of the valve described herein.
• the two stage proportional pressure control valves described therein have an inlet, an outlet, a valve seat between the inlet and outlet, and a valve poppet which can be moved toward or away from the valve seat to vary the cross section of the passage from the inlet to the outlet so as to vary the flow of fluid from the inlet to the outlet. Fluid from the inlet also flows through the poppet to a chamber behind the poppet which is vented through a variable restriction.
• the restriction is varied by moving an armature toward or away from it, the armature being propelled by a magnetic field generated by an electromagnetic coil.
• the pressure in the chamber behind the poppet drops, thereby increasing the pressure difference across the poppet . This tends to move the poppet away from the seat, increasing flow from the inlet to the outlet.
• the pressure difference across the poppet is reduced, which has the effect of moving the poppet toward the valve. seat thereby reducing the flow from the inlet to the outlet.
• the present invention provides a two stage valve which overcomes the above problem in a design which is economical, efficient and easy to manufacture.
• the invention provides a two stage pressure control valve having a poppet movable toward and away from a valve seat to vary the cross-sectional area of a passageway from an inlet to an outlet.
• the position of the poppet is dependent in large part on the difference in pressure between a fluid pressure at the inlet which exerts a force on the poppet in one axial direction and a control pressure which is produced by a fluid flow from the inlet in a chamber downstream from the inlet and which exerts a force on the poppet in the opposite axial direction.
• the control pressure is controlled by an electromagnetic coil which can be variably energized to move an armature so as to vary a variable restriction downstream from the control pressure, or hold the armature against the restriction with a variable force, so as to balance against the control pressure, thereby controlling the pressure differential across the main poppet.
• the chamber is in communication with the variable restriction through at least one orifice upstream of the variable restriction. The orifice prevents rapid changes in the pressure inside the chamber so as to damp the chamber pressure, and therefore damp movements of the poppet. In this way, the unstable chattering response of the prior valve under certain flow conditions is eliminated.
• one or more additional orifices are provided in the flow path from the inlet to the variable restriction.
• the chamber orifice opens into an unrestricted passageway fed by an upstream orifice which is in communication with the inlet and depleted by a downstream orifice which is in communication with the variable restriction.
• the upstream and downstream orifices are in direct communication with one another and the chamber orifice does not interfere with and is independent of the direct communication between the upstream and downstream orifices.
• fluid is channeled from the inlet to the variable restriction through a tube which extends through the poppet, the chamber being defined adjacent to an outer surface of the tube.
• the orifice extends through a wall of the tube between a lumen of the tube and the chamber, and the tube and poppet form a sliding seal with one another.
• Fig. 2 is an enlarged sectional view of an orifice tube assembly for the valve of Fig. 1;
• Fig. 3 is a hydraulic schematic diagram of the valve of Fig. 1.
• a valve 10 of the invention is particularly, although not necessarily, adapted for incorporation into a suspension damper in the same manner as the valve 500 or 600 described in U.S. Patent Number 5,069,420, the disclosure of which is hereby incorporated by reference.
• the valve 10 is not limited to this application, however, ⁇ and could be applied to a wide variety of other applications such as, for example, a pump control circuit, a fan control circuit or a system relief valve.
• the valve 10 includes a body subassembly 12 having a steel body 14 brazed to one side of a stainless steel ring 16 and a steel cap 18 brazed to the opposite side of the ring 16.
• the body subassembly 12 defines an exterior cylindrical surface onto which is pressed an electromagnetic coil subassembly 20 having a coil 22 and a cover 24. Leads 26 of the coil exit the coil subassembly 20 through the cover 24 and are secured in the coil subassembly 20 by potting compound or plastic overmolding 28.
• the body subassembly 12 also defines an internal cylindrical armature bore 29 in which an armature 30 is received to slide axially.
• the armature 30 includes a steel body 32 plugged with a stainless steel pin 34 which is pressed into a bore of the body 32.
• a passageway 36 extends axially through the armature body 32 to equalize the pressures acting on the opposed axial sides of the armature 30.
• the passageway 36 terminates in an orifice 38 which helps restrict rapid flows between the opposed axial sides of the armature 30.
• Pin 34 is positioned to seat against a nozzle 40 formed around an aperture 42 in a steel nozzle plate 44.
• the direction of flow through the aperture 42 is from the aperture 42 toward the armature 30.
• the armature 30 is not biased against the nozzle 40. Therefore, the aperture 42 is normally open.
• the invention could be practiced with an armature 30 which was normally closed, for example, by being biased against the nozzle 40 by a spring. In that case, the configuration of parts could be changed so that an increase in current would tend to move the armature 30 away from the nozzle 40.
• the coil 22 is energized via leads 26 to force the armature 30 toward the nozzle 40 so as to vary the restriction through the aperture 42 formed between the nozzle 40 and the pin 34.
• the nozzle plate 40 is secured in a cylindrical bore of the body 14 by a lower body 50 which is screwed into the body 14 and seats against the nozzle plate 44, holding the nozzle plate 44 in position.
• the lower body 50 defines an outlet port 52 which is in communication via passageways 54, 56, 58 and 60 with the armature bore 29.
• the outlet port 52 and outlet port 62 (multiple outlet ports may be provided spaced around the circumference of body 50) opens into the side of a poppet bore 64 formed in the body 14.
• a cup-shaped poppet 66 is received in the poppet bore 64 for axial sliding relative thereto and has a forward frusto-conical exterior surface 68.
• the surface 68 is for seating against a mating interior frusto-conical surface 70 formed on the body 14 positioned upstream of outlet 52 and downstream of inlet port 72.
• Both the poppet 66 and the armature body 32 have circumferential grooves as shown to help balance pressures generated by fluid leakage past the circumferences of the respective poppet 66 and armature body 32, as is well known in the art.
• the poppet 66 is made of steel and a brass bushing is pressed into a bore at the inlet end of the poppet 66 so as to create a fluid-tight fixed connection between the bushing 74 and the poppet 66.
• a compression spring 76 extends between the interior surface of the forward wall of the poppet 66 and the nozzle plate 44. The spring 76 biases the poppet 66 against surface 70 so that the flow path between the inlet 72 and the outlet 52 is normally closed.
• An orifice tube assembly 80 (Fig. 2) includes a steel tube 82 which is pressed into a forward facing bore of nozzle plate 44 so as to create a fluid-tight fixed connection between the tube 82 and the plate 44.
• a forward orifice 84 and a rearward orifice 86 are formed in respective orifice inserts which are pressed into the tube 82 so as to create a fluid tight seal between the respective orifice insert and the tube 82.
• a filter screen 88 is pressed into the tube 82 upstream of the forward orifice 84.
• the forward end of the tube 82 is received in the brass bushing 74 in a close sliding fit so as to create a substantially fluid-tight seal between the brass bushing 74 and the tube 82 but allow sliding of the poppet 66 relative to the orifice tube assembly 80.
• an orifice 90 is formed in the wall of the tube 82 which communicates lumen 92 of tube 82 with chamber 94 defined around the exterior surface of tube 82, in which spring 76 resides. Fluid pressure in chamber 94 tends to urge poppet 66 toward seat 70 such that poppet 66 normally closes the passage between inlet 72 and the outlets 52, 62.
• the chamber 94 is defined by the area of the poppet bore 64 exposed in the chamber 94, the exterior cylindrical surface of tube 82, and the interior surfaces of nozzle plate 44 and poppet 66 which are exposed in chamber 94. Except for leakage which may occur between the poppet 66 and the poppet bore 64 and between the brass bushing 74 and the tube 82, which is negligible, the only passageway for fluid into or out of the chamber 94 is the orifice 90. In the preferred embodiment of the three orifices
• the orifice 90 is the smallest, in the preferred embodiment being .0098 inches in diameter.
• the orifice 84 is .0118 inches in diameter and the orifice 86 is .0156 inches in diameter.
• the forward orifice 84 is capable of delivering a larger flow rate than the orifice 90
• the orifice 86 is capable of delivering a larger flow rate than either the orifice 84 or the orifice 90, for a given pressure differential.
• the orifice 90 is sufficiently small so as to restrict relatively rapid flows into or out of the chamber 94. This has the effect of damping the pressure in chamber 94 so that for rapid changes in the pressure at inlet 72, the pressure in chamber 94 changes more slowly. Thus, the movement of poppet 66 is damped, eliminating instability and resultant chattering of the valve 10.
• 0-rings 96 and 98 are provided to provide sealed interfaces with the manifold of the system into which the valve 10 is incorporated such as, for example, with the valve cavity of the suspension damper as described in U.S. Patent Number 5,069,420 referred to above.
• poppet 66 may initially open allowing relief of the pressure to outlet 52 at least until the fluid from inlet 72 flows through orifice 84 and 90 and fills chamber 94 helping to balance the pressure forces acting on the poppet.
• spring 76 holds the poppet 66 closed, holding the poppet 66 in abutment with seat 70. This is the case when the coil 22 is hard on, so that the stainless steel pin 34 is seated against nozzle 40, completely closing off flow through aperture 42.
• Fig. 3 illustrates a schematic diagram of the valve 10. Elements shown in the schematic of Fig. 3 are labeled with the same reference numerals as were used for the same elements in Figs. 1 and 2.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Mechanical Engineering (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Magnetically Actuated Valves (AREA)
• Valves And Accessory Devices For Braking Systems (AREA)
• Vehicle Body Suspensions (AREA)
• Fluid-Pressure Circuits (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (2)

Family

ID=22148941

Family Applications (1)

Country Status (7)

Families Citing this family (19)

Citations (3)

Family Cites Families (2)

• 1993
  • 1993-06-17 US US08/079,182 patent/US5328147A/en not_active Expired - Fee Related
• 1994
  • 1994-04-01 CA CA 2165455 patent/CA2165455A1/en not_active Abandoned
  • 1994-04-01 AU AU70911/94A patent/AU672713B2/en not_active Ceased
  • 1994-04-01 WO PCT/US1994/003421 patent/WO1995000349A2/en active IP Right Grant
  • 1994-04-01 DE DE1994613686 patent/DE69413686T2/de not_active Expired - Fee Related
  • 1994-04-01 JP JP50277895A patent/JPH08511854A/ja active Pending
  • 1994-04-01 EP EP95904336A patent/EP0702632B1/en not_active Expired - Lifetime

Patent Citations (3)

Non-Patent Citations (1)

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